Internal-combustion engine



March 13, 1928. I 7 1,662,590

j H. THORMEYER I INTERNAL COMBUSTION ENGINE Filed June 16' 1926 Fig.1.

' I em ffimie W,

Patented Mar. 13, 1928.

UNITED STATES I I 1,6sz,59o

PATENT OFFICE.

HANS TEOBMEYER, QI' IBERLIN, GERMAI TY.

INTERNAL-COMBUSTIOH ENGINE.

Application filed June 18, 1928, Serial No. 116,265, and in Germany May 28, 1925.

My invention consists in a compound internal combustion engine.

In the well-known compound internal combusti on engines, there are large losses in heat, that is to say, in energy, because the intermediate connections between the high pressure stage and the low pressure stage must be thoroughly cooled in order to maintain a practicable working temperature and prevent injuryt to the engine parts by the hot exhaust gases, as overheating may render the engine unworkable. Moreover in the familiar engines the heat is not uniformly distributed throughout the whole system and thus stresses are set-up in the material.

The present invention is an engine which aims to avoid said defects illustrated diagranmiatically by way of example, in the ac-' the low pressure piston. Thewaste heat from the hi h pressure cylinders, as it escapes throng the lower ports d and the upper valves 0, is immediately distributed.

This is'indicated in connection with one of the high pressure cylinders on the left hand side in Fig. 1, while the admission of the supplementary charge into the high pressure cylinder is shown on the right hand side the working effect thereof being displaced through 360.

In the illustration according to Fig. 1, the piston of theleft high-pressure cylinder 0 as completed its working stroke, and the combustion products are being exhausted through the ports (1, which have been cleared by the piston. Because of this escape of the combustion products from the left highpressure cylinder, a' considerable increase in pressure is produced in the law-pressure cylinder, which increase in ressure also is transmitted to the right hig -pressure cylinder through the open ports d, with the r esult th t the previously compressed charge of fresh air in the right high-pressure cylinder is still further compressed, as the valve 6 in the right high-pressure, cylinder has already been closed. In view of this in creased compression of the fresh air charge in the right high-pressure cylinder, the exhaust gases from the left high-pressure cylinder can not enter the right high pressure cylinder, the ports d of which are closed again, before the exhaust gases can travel the long distance from the left to the ri ht high-pressure cylinder. These two cy inders are displaced as to their operation 360? relative to each other.

While during the next stroke, the piston in the left high-pressure cylinder in travelling upwards pushes the combustion products completely out of the cylinder through the open valveie, the piston in the low-pressure cylinder 0 travels downwards, during which strokeuthe energy of the exhaust gases is utilized in the low-pressure cylinder. During this time, the charge of fresh air in the low-pressure cylinder 0 which had previously been drawn into said cylinder through valve opening it is compressed. The piston in the right high-pressure cylinder also travels upwards compressing-the fresh air charge in said cylinder. This position of the various pistons is shown in Fig. 2. Fuel 'is now injected into the right highpressure cylinderthe fuel injection openings are indicated at 5 iii Figs. land 2- and as,th'e charge is ignited by the heat of the compressed air, the piston in the highpressure cylinder travels downwards. The piston of the low-pressure cylinder meanwhile having reached its lower dead center,

has thereby cleared the ports f and 9 so that During the next the upwardly travelling piston of. the low ressure cylinder. compressing the fresh air 1n the lowressure cylinderforces the same into the le high-pressure cylinder through the open valve e, at the same time cooling this valve, which previously had received the heat of the hot exhaust gases.

At the end of the working stroke of the piston of the high-pressure cylinder, the ports at therein are opened, and the escaping exhaust gases again produce in the low-pressure cylinder a pressure increase, which is transmitted also to the left high-pressure cylinder, the valve 0 of which, however, is closed, before the exhaust gases of the right high pressure cylinder have time to travel all the way from the right in Fig. 2 to the left. In a similar manner, the valve 0 of the right high-pressure cylinder is opened only, after the pressure between the high-pressure and low-pressure cylinder has become balanced. The piston in the low-pressure cylinder by the exhaust gases from the right high-pressure cylinder, is forced downwards, compressing the fresh air drawn in through valve it during the preceding upward stroke, the left high-pressure piston compressing the fresh air charge in its cylinder, into which thereupon fuel is injected through the fuel opening 2'. Combustion follows, and at the same time the right highpressure cylinder receives a charge of fresh air, and the cycle commences again.

I claim:

1. A compound internal combustion engine comprising two high pressure engines and an intermediate low pressure engine, said low pressure engine including a stepped piston comprising a cylindrical portion and a disk shaped portion, cylinders for said portions, a conduit connecting the said cylinders, an air intake port in the cylinder containing the disk shaped portion, an exhaust port in the cylinder containing said cylindrical portion, and a valve in the cylinder of each high pressure engine receiving compressed air from, and exhausting products of combustion to, said conduit.

2. In combination with the structure claimed in claim 1, a supplemental port in each high pressure cylinder con'muinicating with said conduit at the end of the high pressure stroke.

In testimony whereof I have afiixed my signature.

HANS THORMEYER. 

